This invention relates to a system for analyzing the effects of high energy ion radiation upon materials and the function of semiconductor electronic circuits, ion beam analysis. More particularly it relates to a system for correlating the impact point of an ion as a function of the mapped origination point of the secondary electrons that are emitted with the effect(s) of that ion upon the sample itself.
Nuclear microprobe analysis is currently performed by focusing MeV ions onto a sample and then scanning the ion beam in a flying spot analysis. The nuclear, atomic, or charge collection signals that are created by the interaction of the ions with the sample constitute the detected signal. The location from which the signal originates on the sample is known by the position of the scanning ion beam at the time the signal is created and detected. The position of the "flying spot" is derived from the scanning apparatus that moves the focussed ion beam spot back and forth across the sample. Analytical techniques using nuclear microprobe analysis have reached a 0.3-0.9 micron lower limit for the beam spot resolution with presently available magnetic and electrostatic focusing lenses. No significant improvements in spatial resolution have been reported in over 5 years. There are a variety of factors involved in this stagnation that include the difficulty in manufacturing the lenses for these ion beams with the required accuracy, the difficulty in achieving the required level of vibration isolation, and the difficulty in focussing ions with high magnetic rigidity and/or poor chromaticity originating from cyclotrons, linacs and older Van de Graaff style electrostatic ion accelerators. There is a present need in the art to improve the spatial resolution for this analysis technique, a need that will only become more critical as the feature sizes of microelectronic circuits continue to shrink. There is also a need to provide performance that is equivalent or better than the present state of the art at a greatly reduced cost.